Video error detection, recovery, and concealment

• US 20060013318A1
• Filed: 06/22/2005
• Published: 01/19/2006
• Est. Priority Date: 06/22/2004
• Status: Abandoned Application

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Webb, Jennifer, Fernandes, Felix C.A.
• Application Number:
  US11/158,974
• Publication Number:
  US 20060013318A1
• Time in Patent Office: Days
• US Class Current: 375/240.250
• CPC Class Codes: H04N 19/174 the region being a slice, e.g. a line of blocks or a group of blocks
• CPC Class Codes: H04N 19/44 Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
• CPC Class Codes: H04N 19/65 using error resilience
• CPC Class Codes: H04N 19/70 characterised by syntax aspects related to video coding, e.g. related to compression standards
• CPC Class Codes: H04N 19/89 involving methods or arrangements for detection of transmission errors at the decoder
• CPC Class Codes: H04N 19/895 in combination with error concealment
• CPC Class Codes: H04N 19/91 Entropy coding, e.g. variable length coding [VLC] or arithmetic coding

Abstract

Decoding for H.264 with error detection, recovery, and concealment including two parsing functions for efficient detection of errors in exp-Golomb codewords, recovery for error in the number of reference frames, skipping to an uncorrupted SPS/PPS NAL unit, and concealment of invalid gaps in frame number by separate gap size 2 and greater than size 2 analysis.

Claims

1. A method of decoding codewords with a variable number of leading 0s, comprising:

(a) providing a maximum for the number of leading 0s in a codeword;

(b) checking whether the number of leading Os of a received codeword exceeds said maximum;

(c) when said checking of step (b) indicates said received codeword has more leading 0s than said maximum, reporting an error.

2. The method of claim 1, wherein:

(a) said maximum is selected from the group consisting of 15 and 31.

3. A method of managing a decoded picture buffer, comprising:

(a) providing a maximum for the number of short-term items plus the number of long-term items in a decoded picture buffer;

(b) when the number of short-term items plus the number of long-term items in said decoded picture buffer exceeds said maximum, indicating an error;

(c) when either (i) said step (b) indicates an error or (ii) said number of short-term items plus number of long-term items equals said maximum, marking one of said short-term items as unused.

4. A method of parsing an encoded video stream, comprising:

(a) receiving a sequence of network abstraction layer units;

(b) when an error is detected in a sequence parameter set (SPS) unit or a picture parameter set (PPS) unit in said sequence, discard said SPS unit or PPS unit, respectively, and reuse a prior SPS unit or PPS unit which is error-free, respectively.

5. The method of claim 4, wherein:

(a) when in step (b) of claim 4 there is no prior SPS unit or PPS unit which is error-free, respectively, discard units in said sequence until an error-free SPS unit or PPS unit, respectively, is found.

6. A method of video decoding, comprising:

(a) receiving a sequence of slices of frames;

(b) when a frame number of a slice differs from a frame number for the previous slice by more than 2, then change said frame number of said slice.

7. The method of claim 6, wherein:

(a) when said slice is not part of a reference frame, said step (b) of claim 6 changes said frame number of said slice to said frame number for the previous slice.